Preheat oven to 350 degrees. Grease the inside of a medium casserole dish. Prepare the wild rice according to the package directions. Meanwhile, place the sausage in a medium skillet over medium heat and cook until browned, breaking up clumps. Transfer the sausage to a large bowl and pour off all but 2 tbsp. of the drippings from the skillet. Add the celery and onion to the skillet and cook until crisp tender, stirring frequently. Add the vegetables to the sausage along with the wild rice, thyme, sage, salt and pepper and stir to combine. Spoon the rice mixture into the prepared dish and bake about 30 minutes until heated through.